Compact ink jet recording apparatus with particular design for recording medium conveyance and support

ABSTRACT

A recording apparatus for effecting recording on a recording medium has a recording head for effecting recording on the recording medium, conveying rollers for conveying the recording medium, a first and a second case for covering the recording head and the conveying means, and a mechanism for effecting relative movement of the first case and the second case.

This application is a continuation of application Ser. No. 07/803,604filed Dec. 9, 1991, abandoned, which is a divisional of application Ser.No. 07/353,000, filed May, 17, 1989 now U.S. Pat. No. 5,105,210.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a recording apparatus for effecting recordingon a recording medium such as a recording sheet.

The present invention can be suitably applied to a recording apparatussuch as a printer or a facsimile apparatus in which a recording head iscarried on a carrier reciprocally movable in the widtwise direction of arecording medium and recording is effected while main scanning iseffected in a direction perpendicular to the direction of feeding of therecording medium.

2. Related Background Art

A serial recording apparatus will hereinafter be described as anexample.

The prior-art serial recording apparatus is of such structure that aguide shaft for guiding a carrier is fixed between the right and leftframe members of the apparatus body and the shafts of a sheet feedingroller for conveying a recording sheet and a guide roller are rotatablysupported, and the range of movement of said carrier and the lengths ofsaid rollers are set to dimensions which cover the greatest recordablesheet width.

Now, the determination of the greatest recordable sheet width is donewith that sheet width taken into account though it may be used rarely,and therefore, the greatest recordable sheet width is generally muchgreater than the sheet width used usually.

Therefore, the widthwise dimension of the recording apparatus alsogenerally becomes greater than necessary when viewed from its daily use.

However, the intermediate portion in the widthwise direction of theserial recording apparatus is merely a space for securing the movementdistance of the carrier and therefore, the use of a recording apparatusof great width which takes into account recording sheets only rarelyused as previously mentioned has led to the possibility of the apparatusbecoming uneconomical in terms of space.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a recordingapparatus having a variable size apparatus body.

It is another object of the present invention to provide a recordingapparatus for which the custody space during non-use can be made small.

It is still another object of the present invention to provide arecording apparatus in which the size of the apparatus body can bevaried in accordance with the size of a recording medium on whichrecording is to be effected, thereby achieving high efficiency of theinstallation space for the apparatus during use.

It is yet still another object of the present invention to provide anink jet recording apparatus in which the possibility of the apparatusbeing left without the recording head thereof being capped duringnon-use or custody can be prevented and the smoothness of starting ofthe apparatus during re-use is realized.

It is a further object of the present invention to provide a recordingapparatus in which the widthwise dimension of the apparatus body isdetected and the range of reciprocal movement of recording means isdetermined in conformity with the result of the detection.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing a state in which a serial recordingapparatus according to an embodiment of the present invention is used.

FIG. 2 is a fragmentary perspective view taken along line II--II in FIG.1.

FIG. 3 is a perspective view showing the recording apparatus of FIG. 1as it is contained.

FIG. 4 is a perspective view of a serial recording apparatus accordingto another embodiment of the present invention.

FIG. 5 is a cross-sectional view of the pivotally connected portion of aplate member in FIG. 4.

FIG. 6 is a perspective view showing a state in which the recordingapparatus of FIG. 4 is used.

FIG. 7 is a perspective view showing the recording apparatus of FIG. 5as it is contained.

FIG. 8 is a perspective view showing the internal structure of therecording apparatus according to the present invention.

FIG. 9 is a cross-sectional view of the inserted and fitted portion of aguide shaft in FIG. 8.

FIG. 10 is a cross-sectional view of a half portion of the shaft of FIG.9.

FIG. 11A is a cross-sectional view of another form of a feed rollershaft in FIG. 8, and FIG. 11B is a side view thereof.

FIG. 12 is a fragmentary perspective view of a rack for driving acarrier in FIG. 8.

FIG. 13 is a perspective view showing a second example of theconstruction of the carrier driving device.

FIG. 14 is a perspective view showing a third example of theconstruction of the carrier driving device.

FIG. 15 is a perspective view showing a fourth example of theconstruction of the carrier driving device.

FIG. 16 is a schematic plan view of slack eliminating means for flexiblewiring when extended.

FIG. 17 is a schematic plan view of the means of FIG. 16 when reduced.

FIG. 18 is a schematic plan view showing the locked state of a lockmechanism.

FIG. 19 is a schematic plan view showing the unlocked state of the lockmechanism of FIG. 18.

FIG. 20 is a perspective view showing a second example of theconstruction of width detecting means.

FIG. 21 is a schematic plan view showing a third example of theconstruction of the width detecting means.

FIG. 22 is a block diagram of the control system of the recordingapparatus of FIG. 8.

FIG. 23 is a flow chart of the margin setting operation of the controlsystem of FIG. 22.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention will hereinafter be described specifically withreference to the drawings.

FIG. 1 is a perspective view showing a state in which an embodiment of aserial recording apparatus capable of expansion and contraction in itswidthwise direction is used, FIG. 2 is a fragmentary view taken alongline II--II of FIG. 1, and FIG. 3 is a perspective view of the recordingapparatus of FIG. 1 as it is reduced (contained).

Referring to FIGS. 1-3, the serial recording apparatus shown is designedsuch that cases 1 and 2 and a recording mechanism therein can beexpanded or contracted in the direction of movement of a carrier (thedirection of arrow A) to thereby increase or decrease the widthwisedimension of the apparatus and when the apparatus is to be contained, itcan be reduced to its minimum width as shown in FIG. 3.

The cases are of such structure that the outer surface of a half 1 ofthe apparatus body provided with a main switch (a power source switch)3, various touch switches 4 (such as for setting the size, setting thenumber of sheets and setting the density) and an interface connector 5for connection to an outside input instrument such as a personalcomputer has another half 2 of the apparatus body on the cover sidethereof slidably fitted thereto. The cases are also of such structurethat the widthwise dimension thereof can be freely selected by beingheld by click action at a plurality of positions conforming to thewidths of recording sheets 6 used, such as not only the position for thepaper size A4 shown, but also positions of small widths for size B5 andpostcard size and positions of great widths for sizes B4 and A3.

That is, in the present embodiment, the outer case of the apparatus bodyis divided into two, a convex portion 2a provided on the case 2 isbrought into engagement with a concave rail 1C provided on the frontside plate 1a of the case 1 and the case 2 is made slidable relative tothe case 1. The convex portion 2a is formed of an elastic material suchas plastic, and by this convex portion 2a fitting to one of cut-aways 1din the rail 1c provided in conformity with the various sizes ofrecording sheets, the case 2 can be fixed by click action. On the case1, the main switch 3 is provided projecting from the front side plate1a, and the touch switches 4 are provided in the recess of the uppersurface 1b of the case 1c, and further, size indicating portions a, band c are provided on the upper surface 1b. Also on the case 2, acut-away 2b is provided at a location opposed to the main switch 3, anda handle portion 2c for use when the case 2 is to be slid is provided.

When the apparatus is not being used, as shown in FIG. 3, the cases 1and 2 may be pushed into each other and be held at the position of theminimum width (the containment width) by click action.

Further, in the upper surface 1b of the cases 1 and 2, a slit-likeinsertion port 7 for inserting therethrough the recording sheet 6 foreffecting recording thereon and a discharge port 8 for dischargingtherethrough the recording sheet 6 after recording are formed astridethe two cases 1 and 2. The lengths of the insertion port 7 and dischargeport 8 are variable in conformity with the widthwise dimension of thecases 1 and 2 and are set to a value suitable for the insertion of therecording sheet 6 used.

As is apparent from FIGS. 1 and 3, in the state in which the widthwisedimension of the recording apparatus has been made minimum with thecases 1 and 2 sufficiently pushed into each other (FIG. 3), theinterface connector 5 for connection to the outside input such as apersonal computer which is provided in the recess of the rear sidesurface 1c of the case 1 of the apparatus body side and the switches 4are fully covered with the case 2 of the cover side so that no dustenters the interior of the recording apparatus. A recess may be providedin the inner surface of the case 2 so that the switches 4 may projectfrom the upper surface of the case 1.

In this manner, a protective cover for the connector 5 and the switches4 is formed by the cases 1 and 2 themselves which are fitted togetherfor expansion and contraction, and a dust-proof structure is constructedwhich prevents the entry of dust from the switches and connection into acontrol circuit or the like in the apparatus without requiring anyadditional parts.

Also, the main switch 3 mounted on the side surface 1a of the case 1 ofthe apparatus body side is disposed so that the power source of theentire apparatus is switched OFF by the cut-away 2b of the case 2 cominginto engagement with the switch 3 in response to the movement of thecase 2 in the direction of closing to thereby move the switch 3 to itsOFF position when the widthwise dimension of the recording apparatus(the cases 1 and 2) reaches its minimum or the vicinity thereof. Thus,after the completion of printing, the main switch 3 can be reliablyopened simply by containment, and the problem of forgetting to cut offthe power source can be eliminated.

Further, pedestals 10 of rubber-like elastic material are attached tothe bottom surfaces of the cases 1 and 2, and the pedestals 10 attachedto the apparatus body side function as stopper for regulating theminimum width (the containment width) when the cases 1 and 2 are fittedtogether into their smallest sizes as shown in FIG. 3.

FIG. 4 is a perspective view of another embodiment of the serialrecording apparatus capable of expansion and contraction, FIG. 5 is across-sectional view of the pivotally connected portion of a platemember in FIG. 4, FIG. 6 is a perspective view showing a state in whichthe recording apparatus of FIG. 4 is used, and FIG. 7 is a perspectiveview showing a state in which the recording apparatus of FIG. 4 is innon-use (in custody or contained).

The embodiment of FIGS. 4-7, like the embodiment of FIGS. 1-3, isdesigned such that the widthwise dimension of the apparatus is increasedor decreased by the cases 1 and 2 and a recording mechanism therein (seeFIG. 8) being expanded or contracted in the direction of movement of thecarrier.

The present embodiment is of such structure that a plate member(opening-closing member) 11 is mounted on the cases 1 and 2 for pivotalmovement about a horizontal axis B and sliding movement in a horizontaldirection by a mechanism which will be described later and the platemember 11 is erected to bring about a state of use (an opened state)shown in FIG. 6, whereby there is constituted a sheet support forholding the recording sheet 6 to be inserted into the insertion port 7or to be discharged from the discharge port 8, and by the cases 1 and 2being brought into the minimum width (contained) state and the platemember 11 being brought down (onto the upper surface 1b of the case 1)as shown in FIG. 7, there is formed a cover on the cases 1 and 2.Designated by 2e is a lock member adapted to be engaged with arestraining portion 2g for the plate member 11 to thereby maintain theplate member 11 unlocked.

Now, the opening-closing mechanism of the plate member 11 is mounted forsliding movement in the widthwise direction of the cases 1 and 2 andpivotal movement about the axis B by a bead portion (shaft portion) 12being pivotably fitted into a circular groove 13 provided in a base 13formed astride the cases 1 and 2 and along the sheet insertion port 7 inthe cases 1 and 2 integral with the plate member 11, as shown in FIG. 5.The plate member 11 is maintained in its opened state is accomplished bythe rear surface 11a thereof being caused to bear against the uppersurface 13b of the base 13.

FIG. 4 shows a state in which the plate member 11 is erected (opened)and the cases 1 and 2 are extended to a predetermined width (size A4).In the state of use (the opened state) of the plate member 11 shown inFIG. 6, the plate member 11 is slid to the central position of the sheetinsertion port 7 and is set at a position whereat the recording sheet(not shown) can be held with good balance and thus, a sheet supporter isconstituted.

The fitting of the spherical edge portion 12 of the plate member 11 intothe groove 13 in the cases 1 and 2 can be accomplished by the operatormanually sliding the plate member 11, but it is preferable to adopttight fitting which can hold the spherical edge portion at any positionby a frictional force, and in some cases, it is also possible to adopt astructure for holding the spherical edge portion at a positioncorresponding to the sheet size by click action.

As described above, the serial recording apparatus capable of expansionand contraction shown in FIGS. 4-7 differs from the embodiment of FIGS.1-3 in that there is added the collapsible plate member 11 whichfunctions as a sheet supporter during use and functions as a coverduring non-use, and in the other points, it is substantially similar tothe embodiment of FIGS. 1-3.

Accordingly, in the embodiment shown in FIGS. 4-7, portions similar tothose in FIGS. 1-3 are given similar reference numerals and need not bedescribed.

According to the case structure shown in FIGS. 4-7, the same effect asthat of the embodiment shown in FIGS. 1-3 is obtained and in addition,the provision of the plate member 11 can lead to the provision of amechanism which serves both as a sheet supporter and a cover by a simpleand compact construction.

Now, FIG. 8 is a perspective view showing the internal structure of theserial recording apparatus capable of expansion and contractionaccording to the present invention, and the structure of FIG. 8 isincorporated in the interior of the cases 1 and 2 described withreference to FIGS. 1-7.

In FIG. 8, a left base 15 and a left side plate 16 are fixed to one case1, and a right base 17 and a right side plate 18 are fixed to the othercase 2. Accordingly, the left base 15 and the left side plate 16 and theright base 17 and the right side plate 18 move relative to one anotherin the direction of movement of the carrier with the expansion orcontraction of the cases 1 and 2, and the recording mechanism supportedtherebetween expands and contracts. Two grooves 17a are formed in thebase 17 along the direction of sliding, and a dowel 15a is provided onthe bottom surface of the base 15. So, during the sliding of the cases 1and 2, the dowel 15a comes into engagement with the grooves 17a andmoves therein and therefore, the sliding of the cases 1 and 2 isaccomplished well.

First, a feed roller shaft 20 capable of expansion and contraction isrotatably journalled to the left and right side plates 16 and 18. Aguide shaft 21 capable of expansion and contraction is fixed forwardlyof and parallel to the feed roller shaft 20. Sheet feed driving rollers22A and 22B made of hard rubber or like material are fixed to theopposite end portions of the feed roller shaft 20, i.e., the immediateinner portions of the side plates 16 and 18. The sheet feed drivingrollers 22A and 22B are driven by a sheet feed motor 27 through theshaft 20.

Here, the feed roller shaft 20 and the guide shaft 21 are designed toexpand or contract freely in conformity with the increase or decrease inthe spacing between the side plates 16 and 18 caused by the expansion orcontraction of the cases 1 and 2.

The expansion and contraction of the feed roller shaft 20 and the guideshaft 21 will now be described.

FIG. 9 shows a cross-section of the expansible and contractible slidefitting portion of the feed roller shaft 20 and the guide shaft 21, andFIG. 10 shows a cross-section of one of the shafts of FIG. 9.

That is, the feed roller shaft 20 and the guide shaft 21 are oftwo-division structure in which they are slidably connected together byan axial dovetail groove, and the left and right halves 20A (21A) and20B (21B) thereof are of a partly arcuate cross-sectional shape in whichthe fitting portions for receiving the partners are cut away. The leftand right shaft portions 20A (21A) and 20B (21B) are slidably fitted toeach other, and further, a guide roller 24 for supporting theintermediate portion of the sheet 6 (FIG. 1) conveyed by rollers 22A and22B is slidably fitted to the outer periphery of the intermediateportion of the shaft 20. That is, the inner diameter 24a of the roller24 is made slightly greater than the outer diameter of the shaft 20, andthe roller 24 is provided for sliding movement along the shaft 20 andfor idle rotation.

Further, compression springs 23A and 23B of equal resilient forcesfitted to the shaft 20 are mounted between the opposite end surfaces ofthe guide roller 24 and the inner end surfaces of the left and rightfeed rollers 22A and 22B. Thus, the guide roller 24 is subjected to theequal spring forces of the springs 23A and 23B from the opposite sidesthereof even when the shaft 20 expands or contracts, whereby it isresiliently held at a predetermined position (usually the substantiallycentral position) on the shaft 20.

Furthermore, pinch rollers 25 (only the left one of which is shown) areadapted to be urged against the recording sheet entrance side of theleft and right feed rollers 22A and 22B by a spring force. That is, thepinch rollers 25 are biased by a compression spring 25a and held by alever 25b pivotable about a shaft 25c to thereby press the rollers 22Aand 22B. Still further, paper pans 26A and 26B which form apredetermined gap between the peripheral surfaces of the left and rightfeed rollers 22A and 22B and function as a sheet keeper and a sheetguide are fixed along said peripheral surfaces.

According to the above-described sheet feeding mechanism, the spacingsbetween the left and right feed rollers 22A and 22B, between the leftand right sheet keepers 26A and 26B and between the left and right pinchrollers 25 can be increased or decreased in conformity with the sheetwidth and therefore, independently of the sheet width, a sheet feedingforce can always be imparted to the widthwisely opposite end portions ofthe sheet 6 and thus, smooth and accurate sheet feeding without any skewfeeding can be accomplished.

In the aforedescribed embodiment, there has been shown an example inwhich the guide roller 24 is provided for idle rotation on the shaft 20,but alternatively, the guide roller 24 may be constructed so as to berestrained on the shaft 20 so that a driving force may be imparted tothe guide roller 24. In such case, an elongated groove is formed in theshaft 20 along the direction of sliding, and a dowel is provided on theinner surface of the roller 24. In this manner, the dowel is broughtinto engagement with said groove, whereby the roller 24 is rotativelydriven in accordance with the rotation of the shaft 20 and the roller 24is slidable in the thrust direction. Such a construction is particularlyeffective for the conveyance of recording sheets of small sizes.

Also, a carrier 28 is slidably supported on the guide shaft 21. Arecording head 31 is carried on the carrier 28. Here, the recording head31 shows the case of an ink jet recording head with an ink tank, and thefront face of the head 31 is provided with a plurality of ink dischargeports (not shown) for forming flying ink droplets by the action ofelectro-thermal converting elements driven in accordance with imageinformation. Accordingly, the ink droplets are of the so-called impacttype which flies from the discharge ports toward the recording sheet 6to thereby accomplish recording.

The guide shaft 21, like the feed roller shaft 20, is of two-divisionstructure in which the left and right halves are slidably connectedtogether by an axial dovetail groove, and the left and right halves 21Aand 21B are of a partly arcuate cross-sectional shape in which thefitting portions for receiving the partners are cut away as shown inFIG. 10.

Thus, the guide shaft 21 also is constructed for expansion andcontraction with the cases 1 and 2, in conformity with the widthwiseexpansion and contraction of the apparatus.

The guide shaft 21 needs to guide the carrier 28 accurately andtherefore, needs to have a cross-sectional shape which will not causesteps, as shown in FIGS. 9 and 10, but the feed roller shaft 20 will besufficient if connected so as to be capable of transmitting therotational force, and may cause steps to be formed on the intermediateportion thereof.

Now, FIGS. 11A and 11B show a cross-sectional view and a side view,respectively, of the connecting portion of another embodiment of thefeed roller shaft 20.

As shown, one half 20A and the other half 20B of the shaft 20 may be ofa stepped shape similar to that of a square plunger, a square cylinderor the like.

Now, in FIG. 8, a carrier motor 32 for reciprocally moving the carrier28 is carried on the carrier 28 itself. By a pinion 34 which is inmeshing engagement with a rack 33 being rotated, the carrier 28 is movedalong the rack 33. That is, as shown in FIG. 12, the pinion 34 integralwith the motor shaft 32a of the motor 32 provided on the carrier 28 isrotated while meshing with the rack 33, and the carrier 28 is also movedto the left or right in conformity with the direction of revolution ofthe motor 32. Here, the rack 33, like the guide shaft 21, need beexpanded or contracted, and in the shown example, the expansible andcontractible rack 33 is constituted by a convex type tape line which canbe taken up. Also, this rack 33, as shown in FIG. 12, is of structure inwhich meshing holes 35 are formed at a predetermined pitch in a stripplate (usually made of steel) whose cross-section is made arcuate forthe prevention of buckling. So, as shown in FIG. 8, the strip plateconstituting the rack 33 has its fore end coupled to the right sideplate 18, and the base end portion thereof is coupled to the interior ofa convex type case 36 fixed to the base 15 and is normally biased in therolling-in direction by a spring (not shown) in the case 36. Thus, therack 33 is paid away or taken up in conformity with the expansion orcontraction of the cases 1 and 2.

Also, a support roller 37 is provided on the portion opposite to theportion of the carrier 28 fitted to the guide shaft 21, and this supportroller 37 rolls on rails 38A and 38B laid on the upper surfaces of thebases 15 and 17 as the carrier 28 is moved. Accordingly, the carrier 28is guided and supported by the guide shaft 21 and the rails 38A and 38Band can be properly reciprocally moved with a predetermined posture. Anelongate cut-in is provided in the base 15 in side-by-side relationshipwith the rail 38A, and the rail 38B provided on the base 17 movesforward in this cut-in, and the upper surfaces of the rails 38A and 38Bare equal in level.

FIGS. 13 to 15 show second, third and fourth examples, respectively, ofthe construction of the driving device for the carrier 28.

In the second example shown in FIG. 13, the motor 32 for driving thecarrier is fixed to the right base 17, and the carrier 28 may be driventhrough a wire 44 wound on a winding drum 42 rotatable by the motor 32and a tension pulley 43 provided on the left base 15 and having itsopposite ends coupled to the carrier 28. The tension pulley 43 is alwaysbiased in the direction of arrow C by a spring 45 having one end thereofconnected to the base 15, and desired tension is always imparted to thewire 44. So, the spring 45 expands or contracts in conformity with theexpansion or contraction of the cases 1 and 2 and therefore, theexpansion or contraction of the cases 1 and 2 can be well coped with.The carrier 28 carrying thereon the recording head 31 with an ink tank,as in the case of the first example of the construction shown in FIG. 8,is guided and supported by the expansible and contractible guide shaft21 and the rails 38A and 38B. The reference numerals 46 and 47 in FIG.13 designate guide pulleys for guiding the wire 44.

In the third example shown in FIG. 14, a wire 48 having tension impartedthereto is used instead of the guide shaft 21 in FIG. 8. This wire 48has one end thereof connected to the right side plate 18, and the otherend thereof has a tensile force always imparted thereto by a spring 49extended between it and the base 15. In the shown example, theintermediate portion of the wire 48 is guided by a guide pulley 51supported on the base 15, and the spring 49 is connected between a pin15C studded on the base 15 and the end portion 48a of the wire 48.

The carrier driving device shown in FIG. 14 differs from the carrierdriving device in FIG. 8 in that it adopts a mechanism for guiding andsupporting the carrier 28 by the above-described wire 48, instead of theguide shaft 21, but in the other points, it is substantially the same asthe latter, and corresponding portions are given similar referencenumerals and need not be described.

Again the construction shown in FIG. 14, predetermined tension isimparted to the wire 48 by the spring 49 and therefore, the range ofmovement of the carrier can be increased or decreased in conformity withthe widthwise expansion or contraction of the recording apparatus,whereby the carrier 28 can be scanned and driven.

In the fourth example shown in FIG. 15, the motor 32 for driving thecarrier is fixed to the right base 17, and a wire 52 for driving thecarrier 28 is driven by the winding drum 42 rotatively driven by themotor 32. The wire 52 is connected at its opposite ends to the carrier28 and is extended in an endless fashion. That is, the wire 52 wound onthe winding drum 42 over a plurality of turns is connected to theopposite ends of the carrier 28 by way of a movable sheave (tensionpulley) 53 provided on the left base 15, and by the movable sheave 53being pulled by a spring 54 extended between it and the pin 15C of thebase 15, predetermined tension is always imparted to the wire 52 inspite of the expansion and contraction of the apparatus. The referencecharacter 28a designates a passage hole through which the wire 52passes. The reference characters 55A, 55B, 55C and 55D in FIG. 15 denoteguide pulleys for changing the direction of movement of the wire 52.

Thus, in the carrier driving device shown in FIG. 15, the driving andguiding of the carrier 28 is accomplished by the wire 52. That is, thewire 52 of the above-described construction is used instead of theexpansible and contractible guide shaft 21 and the convex type take-uprack 33 shown in FIG. 8.

The fourth example shown in FIG. 15 differs from the carrier drivingdevice of FIG. 8 in the above-described points, but in the other points,it is substantially the same as the latter, and a support roller 37adapted to roll on the rails 38A and 38B laid on the left and rightbases 15 and 17 is supported on the carrier 28.

Again in the construction shown in FIG. 15, predetermined tension isalways imparted to the wire 52 by the spring 54 and therefore, the rangeof movement of the carrier 28 can be increased or decreased inconformity with the widthwise expansion or contraction of the recordingapparatus and the carrier 28 can be scanned and driven by the carriermotor 32.

Further, in the embodiment shown in FIG. 8, cap means 57 for sealing theink discharge opening surface (the printing surface) of the recordinghead (the ink jet head) 31 when the carrier 28 comes to its left endhome position is installed on the left base 15.

As shown in FIG. 8, the cap means 57 is comprised of a cap holder 59slidably and pivotably supported on a guide pin 58 provided along thedirection of movement of the carrier, a cap 61 of rubber-like elasticmaterial attached to the front face (the face opposed to the printingsurface of the recording head 31) of the cap holder 59, a spring 62 forbiasing the cap holder 59 in the direction opposite to the home position(the rightward direction) and moreover in the direction in which the cap61 is retracted (away from the head 31), and a cam 63 for prescribingthe pivoted positions of the cap holder 59 (the spaced-apart and urgedpositions of the cap 61) in conformity with the sliding position of thecap holder 59.

The cap holder 59 is provided with a projection 65 for engaging a hookportion 64 provided on the home position side of the carrier 28 when thecarrier comes close to the left end (the home position).

According to the above-described cap means 57, when the carrier 28 ismoved to the left end, the hook 64 provided on the carrier 28 comes intoengagement with the projection 65 and the cap holder 59 spring-biasedrightwardly is moved along the guide pin 58. As the cap holder 59 ismoved to the left, the cap 61 is moved (toward the head 31) by the shapeof the cam 63 which is also a stop supporting portion, and is pivotallydisplaced in a direction to be urged against the printing surface of thehead 31 (the surface having the ink discharge ports). Thus, with themovement of the carrier 28 to the home position, the printing surface ofthe recording head 31 is automatically sealed by the cap 61. When thecarrier 28 is moved rightwardly from the home position, the cap 61 isautomatically separated from the head 31 by the movement opposite tothat described previously.

Furthermore, in the present embodiment, as shown in FIG. 8, a controlbase plate 67 for controlling the recording apparatus is mounted on theleft base 15, and the electrical connection between the control baseplate and the head driving circuit on the carrier 28 is made by aflexible cable 68. FIGS. 16 and 17 are schematic plan views showing theoperation of guide (slack eliminating) means for the flexible cable 68when the recording apparatus is expanded or contracted.

In FIGS. 8, 16 and 17, during the widthwise expansion or contraction,the right base 17 is moved relative to the carrier 28, and a projection69 which is engaged with the intermediate portion of the flexible cable68 and functions as a guide pin is studded on the base 17. The left base15 is formed with a slot 71 for passing the projection 69 therethroughand permitting the movement thereof.

So, when the degree of expansion or contraction of the recordingapparatus exceeds a predetermined level, the flexible cable 68 maycontact with another member such as the recording mechanism or the framemember and be unnaturally curved, whereby during the movement of thecarrier 28, the flexible cable may rub against or bite into other memberand may be damaged thereby, but in the present embodiment, as shown inFIG. 17, when the recording apparatus is contracted, the flexible cable68 is hauled in with the projection 69 as a guide pin and therefore, theflexible cable can be prevented from being caught or damaged.

Description will now be made of a mechanism for preventing thecontraction of the apparatus body during non-capping.

The serial ink jet recording apparatus shown in FIG. 8 is designed suchthat the apparatus cannot be contracted to the minimum width (thecontained state) shown in FIGS. 3 or 7 unless the carrier 28 comes tothe home position and the printing surface of the recording head 31 issealed by the cap 61.

That is, if the power supply is cut off or interrupted during printingand the recording apparatus is contracted and brought into its non-useor custody state with the carrier 28 left stopped at other position thanthe home position, the ink discharge ports of the recording head 31 willbe left in the atmosphere for a long time, and ink will be dried and thesolid components thereof will adhere to the ink discharge ports or dustwill adhere to the ink discharge ports to thereby make it very difficultto start the recording operation when printing is to be resumed.However, in the present embodiment shown in FIG. 8, design is made suchthat the recording apparatus can be contracted to the minimum width (thecontained state) only when the carrier 28 is at the home position (thehead cap position), whereby the above-noted problem of the ink dischargeports being clogged by their being exposed to the atmosphere for a longtime can be solved.

That is, FIG. 18 is a schematic plan view showing a state in which therecording head 31 is not capped and the recording apparatus cannot becontracted to the minimum width, and FIG. 19 is a schematic plan viewshowing a state in which the recording head 31 is capped and therecording apparatus is contracted to the minimum width.

As shown in FIGS. 8, 18 and 19, the slot 71 in the left base 15 isformed sufficiently long to the left position, and a lock pin 72 studdedon the right base 17 extends through and is slidably fitted in the slot71. On the other hand, at a position near the left end of the slot 71 inthe left base 15, a bell-crank-like lock lever 73 is biased clockwise bya spring 75 and supported for pivotal movement about a shaft 73a. Thelock lever 73 is normally caused to bear against a pin 73b by the spring75, and the stopper portion 76 thereof is biased to a position forshielding the slot 71 (FIGS. 8 and 18).

On the other hand, the lock lever 73 is provided with an acting portion77 for causing a pressing arm 74 to strike against the lock lever 73 andpivot the lock lever 73 to its opened position (FIG. 19) when thecarrier 28 comes to the home position (the capping position).

Also, the pressing arm 74 for pivoting the lock lever 73 to its openedposition is provided at the lower end of the carrier 28.

So, when the carrier 28 does not yet come to the home position and thehead 31 is not capped, the stopper portion 76 of the lock lever 73shields the slot 71 and regulates the movement of the lock pin 72provided on the case 2 in the direction to contract the apparatus body,whereby the case is prevented from being contracted to a predeterminedwidth (e.g., the custody width). Accordingly, it can be prevented thatthe apparatus is put into custody without the head 31 being capped. Onthe other hand, when the carrier 28 comes to the home position and thehead 31 is capped, the arm 74 bears against the acting portion 77 topivot the lever 73 counter-clockwise and therefore, the stopper portion76 is retracted from the shielding position in which it shields the slot71, whereby the stopper portion does not interrupt the movement of thecase 2 in the direction to contract. Accordingly, when the head 31 iscapped, the apparatus can be made compact for custody.

The lock pin 72, the lock lever 73 and the pressing arm 74 as describedabove together constitute a forget-to-cap preventing mechanism which isprovided with a stop member 76 released by the movement of the ink jethead (recording head) 31 on the carrier 28 returning to the cap positionand in which when the ink jet head 31 is at a position off the capposition, the lock pin 72 is stopped by the stop member (stopperportion) 76 as shown in FIG. 18 to thereby prevent the contractingoperation of the recording apparatus.

A sheet width sensor will now be described.

As described above, in the present embodiment, in FIG. 8, the sheetwidth sensor 41 installed on the right base 17 constitutes widthdetecting means for electrically detecting the degree of expansion orcontraction, i.e., the widthwise dimension, of the recording apparatus.

This sheet width sensor 41 is provided within the range of scanning ofthe carrier 28, and is connected to a control circuit so as to beoperated by suitable means such as optical or magnetic means when thecarrier 28 has been scanned (moved), and detect the range of reciprocalmovement of the carrier 28, i.e., the widthwise dimension (the degree ofexpansion or contraction) of the recording apparatus, from the positionof the carrier 28 during this operation.

In other words, it is designed so as to be capable of calculating thewidthwise dimension from the timing of the detection signal transmittedfrom the sheet width sensor 41 to the control circuit on the controlbase plate 67 and the position information of the carrier 28 by aprogram.

According to such a sheet width sensor (width detecting means) 41, thesheet width designating operation by the operator can be eliminated andthe control of the margin setting and print format setting of thecarrier 28 conforming to the expansion or contraction of the recordingapparatus body also becomes possible.

FIGS. 20 and 21 are fragmentary perspective views showing second andthird examples, respectively, of the construction of width detectingmeans replacing the above-described sheet width sensor 41.

In the second example shown in FIG. 20, width detecting means isconstituted by a resistor pattern 81 and a common pattern 82 provided onthe control base plate 67 of the left base 15 and a leaf-spring-likecontact 83 mounted on the right base 17 and slidable on said patterns 81and 82.

According to the width detecting means shown in FIG. 20, the widthwisedimension (the degree of expansion or contraction) of the recordingapparatus can be steplessly detected by a variation in the resistancevalue when said contact 83 is slid on said resistor pattern 81 insynchronism with the expansion or contraction of the recording apparatus(or the cases 1 and 2 thereof).

In the third example of the construction of the width detecting meansshown in FIG. 21, a plurality of push button type switches 85A, 85B and85C are provided at predetermined intervals on the control base plate 67on the left base 15, and a pressing piece 86 disposed so as to press theplurality of switches 85A, 85B and 85C in succession in response to theexpansion or contraction is provided on the right base 17, and theseswitches and pressing piece together constitute the width detectingmeans (the sensor for detecting the degree of expansion or contraction).

Thus, there is provided the step detection type width detecting meansconstituted by the plurality of switches 85A, 85B and 85C operated bythe expansion or contraction of the cases 1 and 2.

According to the width detecting means shown in FIGS. 20 and 21, theprint format setting (the margin setting) during recording can also becontrolled at the same time by only the expansion or contraction withoutthe sheet width being designated and in addition, extra wiring andmembers therefor become unnecessary and curtailment of the space andreduction in the cost can be achieved because a detection signalgenerating unit is disposed by the utilization of the control plate 67.The reference numeral 97 designates a transistor such as a memory, CPUor IO, and the reference numeral 98 denotes a buzzer which generatesvarious kinds of alarms.

FIG. 22 is a block diagram of the control system of the above-describedserial recording apparatus of the present invention capable of expansionand contraction.

In FIG. 22, the central processing circuit (the control circuit) 88 ofthe recording apparatus is connected to a host 90 through an interfacecircuit 89, receives command information and recording data, drives therecording head 31 through a head driver circuit 91, drives the carriermotor 32 through a motor driving circuit 92, and further drives thesheet feed motor 27 through a motor driving circuit 93.

A memory unit (RAM) 94 storing the recording data therein is connectedto the control circuit 88, and further, the reference position detectionsignal of the carrier 28 is input from the home position sensor 39 tothe control circuit 88, the sheet presence/absence detection signal ofthe recording sheet 6 is input from a sheet sensor 95 to the controlcircuit 88, and a carrier margin detection signal is input from widthdetecting means 96 comprising the sheet width sensor 41 or the like tothe control circuit 88, and the recording operation is controlled on thebasis of these detection signals.

FIG. 23 is a flow chart of the margin setting operation of the carrier28 by the control system of FIG. 22.

In FIG. 23, at step 100, the voltage source switch is closed or the keyis operated, whereby at step 101, initialization is effected, whereafterat step 102, the carrier motor 32 is driven to move the carrier 28.

While this movement of the carrier 28 is being effected, at step 103,whether the carrier margin sensor (width detecting means) 96 has becomeON is discriminated.

If the carrier margin sensor 96 is OFF, return is made to the step 102,where the movement of the carrier 28 is continued.

When the carrier margin sensor 96 has become ON, advance is made to step104, where the right-hand margin of the carrier 28 is set, and at step105, a print format is set.

Simultaneously therewith, at step 106, the carrier motor 32 is driven toreturn the carrier 28 (usually to the home position), and the marginsetting of the carrier 28 is completed.

As is apparent from the foregoing description, according to the presentembodiment, there is provided a serial recording apparatus having arecording mechanism within cases and wherein the cases, the guide shaftof the carrier and the shaft of the sheet feed roller are expanded orcontracted in the direction of movement of the carrier to therebyincrease or decrease the widthwise dimension and therefore theinstallation space during non-use can be reduced and the installationspace during use can also be set to the necessary minimum in conformitywith the sheet width and which is thus excellent in space efficiency.

While the present invention has been described with respect to an inkjet recording apparatus in which an ink stream is discharged toaccomplish recording, the present invention is not restricted thereto,but is also suitably applicable, for example, to the so-called heattransfer recording system or the so-called thermosensitive recordingsystem.

As described above, the present invention provides a recording apparatuswhose size can be varied.

We claim:
 1. An ink jet recording apparatus for recording using an ink jet recording head for discharging ink from a discharge port to record on a recording medium movable in a conveyance direction, said apparatus comprising:a carriage for moving said ink jet recording head within a moving area in a direction transverse to the conveyance direction of the recording medium; a pair of conveying rollers each having a peripheral surface and being provided along a conveyance route of the recording medium and at opposite sides of the moving area of said carriage, a pair of guide members each having a curved surface disposed along the peripheral surface of a corresponding one of said conveying rollers, said guide members effecting conveying of the recording medium by pinching the recording medium between the peripheral surface of each conveying roller and the curved surface of a corresponding one of said guide members; a roller shaft for supporting said conveying rollers; a rotating member supported by said roller shaft, said rotating member being biased between said conveying rollers by a pair of spring members provided on said roller shaft; and driving means for driving said conveying rollers.
 2. An apparatus according to claim 1, wherein the recording medium contacts only said conveying rollers, said guide members and said rotating member at an area opposite to the moving area of said carriage.
 3. An apparatus according to claim 1, wherein said ink jet recording head includes an electrothermal converting element, and thermal energy generated by said electrothermal converting element causes film boiling in ink to discharge the ink from said discharge port due to a state change caused by growth of a bubble generated by the film boiling. 